Rheostat



G. J. SCHNEIDER.'

(No Model.)

RHEOSTAT.

Patented Nv. 16,1897.

sin!

A r 1111.799/ 0 M UNITED STATES PATENT @OFFICEG on DETROIT, MICHIGAN.

GEORGE J. SCHNEIDER, l

STAT.

SPECIFICATON forming part of Letters Patent No. 593,817, dated November 16, 1897.

Application filed March 5, 1897. Serial No. 626,116. (No model.)

To @ZZ whom it Inm/ concern:

Beit known that l, GEORGE J. SCHNEIDER, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Rheostats, of which the following is a specication, reference being had therein to the accompanying drawings.

My invention relates to that class of rheostats which are adapted to automatically cut out resistance upon theclosing of the electric circuit, and is especially designed to be employed as a motor-starter.

It is the object of my invention to obtain a sim ple construction and one that is absolutely certain in its operation; and to this end my invention consists, iirst, in the means employed for actuating and governing the movement of the movable contact in the operation of cutting out resistance; further, in the means employed for compelling the return of the movable Contact, and, further, in the peculiar construction, arrangement, and combination of part-s, as more fully hereinafter described and claimed.

v In the drawings, Figure l is a perspective view of my rheostat. Fig. 2 is a longitudinal section online no, Fig. 3. Fig. 3 is a cross-section on line y y, Fig. 2. Fig. 4i is a diagram showing the connection with an electric motor.

A is a suitable casing, upon the outer face of which are secured the xed contacts B B, &c., of the rheostat arranged adjacent to each other in the segment of a circle. Projecting from the casing at the center of this segment is the post or stub-axle C, upon which is sleeved an arm D, carrying the movable contact of the rheostat.

E is a gear-segment secured to the arm D and meshing with a pinion F on the shaft G. The shaft G extends into the casing and is connected through the medium of a clutch H with a suitable escapement mechanism I.

J is a circular casing sleeved upon the post C and forming a housing for the spiral spring K, one end of the latter being secured to the housing J and the other endto the arm D.

L and L' are insulated switch-arms secured to the casing J and forming, in connection with the fixed contacts M M and N N', se-

cured on opposite sides of the casing, the circuit-closing switch.

O is an actuating-arm preferably in the form of a bell-crank lever, one arm of which is provided with the lugs a and b, the former extending into the path of the arm D and the latter into proximity to a spring-latch P on the housing J.

Q is a latch-arm secured to the armature of an electromagnet R, arranged Within the casing, which arm projects into proximity to the housing J and is adapted to engage, when the magnet is energized, with a notch c in the casing.

R is an arm extending down from the ar- Inature of the magnet R and forming a stop for the escapement mechanism.

The resistance-coils S S are preferably arranged within the casing on a suitable spider (not shown) and are connected alternately with the contacts B B.

The parts being constructed as shown and described, the arrangement of the electric connect-ions and operation of thedevice when used as a motor-starter are as follows: The main conductors are connected to the contacts M and N. T, U, and V are the bindingposts, secured to the casing, the posts T and U being connected, respectively, with the contacts M and N, while the posts T and V are connected with the iirst two of the contacts B B. The field of the motor is connected between the posts T and V and the armature between the posts U and V. lVhen thus connected, to start the motor the arm O is moved from the position shown in Fig. 2 to the position shown in Fig. l. In making this movement the lug h first strikes against the spring-latch P, turning the housing J upon the post C and against the tension of the spring K and carrying the switch-arms L L into contact, respectively, with the contacts M M and N N', thereby closing the electric circuit through both lield and armature. As the movable contact-arm is still, however, in its initial position, the whole of the resistance-coils S S are in series with the armature. As soon as the switch is closed the magnet R, which is connected in a shuntcircuit, will be energized and will draw the latch-arm Q, into engagement with the notch IOO c, which will hold the casing J from movement, while at the same time the further movement of the arm O will force the lug ZJ past the spring-latch P and into the position shown in Fig. 2. The energizing' of the magnet R will also move the arm R out of engagement with the escapementrmeehanism, allowing the latter to run and the spring K to slowly carry the contact-arm I) around the segment, gradually cutting out the resistance from the arimtture-cireuit. In stopping the motor the arm O is actuated in the reverse direction, and the stop Cl, striking against the arm D, will carry said arm back positively to its initial position, where all the resistance is in. In doing this the clutch II will permit the gear-segment E and pinion F to turn without moving the escapement I. The lug b will also be carried back to a position where it will reengage with the springlatch P, which will force the casing J out of engagement with the latch Q, whereupon the spring K will throw open the switch. In order to insure the positive opening of the switch, a lug (l is placed on the housing J, with which the lug Z2 will engage if it fails to engage with the spring-latch P. Should the current fail at any time when the motor is ruiming, the switch will be immediately thrown open, as the magnet R will release the latch-arm Q and the spring K will force it out of engagement with the notch c. Vhen thus opened, it is impossible to close the switch again until the arm O is carried back to its initial position, and in this movement of said arm the contact-arm I) is compelled to move back to the position where the resistance is all in. rlhus it will be readily seen that with my construction a danger is avoided which is common to automatic devices of this kind-viz., that of failing to always throw the resistance in upon the stopping of the motor. The cutting out of resistance is also very even and gradual, as the escapement mechanism acts as a governor for the spring K, which acts as a time-motor, carrying the arm I) at a uniform speed, and as the reverse movement of the arm rewinds the spring a uniform tension is maintained.

My device is also very simple in construetion and compact, all the parts being secured to the casing A.

Although I have described my device as employed in connection with an electric motor, I do not desire to be limited to this use alone, nor do I wish to limit myself to the precise construction shown and described; but

lVhat I claim as my invention is l. The combination with circuitclosing switch and the movable contact of a rheostat, of a time-motor for actuating said movable contact to cut out resistance adapted to be started upon the closing of the switch, and

means for compelling the return of said movable contact before the opening of said switch.

2. The combination with the circuit-closingI switch and the movable contact of a rheostat, of an escapement-motor for actuating said movable contact to cut out resistance, normally locked from movement, means for closing said switch adapted to simultaneously unlock the escapement, and means for opening said switch adapted to compel the return oi. said contact and to rewind the motor.

8. The combination with the circiiit-closing switch and the movable contact of a rheostat, of an escapement-motor for actuating said movable contact to cut out resistance, normally locked from movement, and means tor closing said switch adapted to simultaneously unlock the escapement, means for opening;I said switch adapted to compel the return ot' said movable contact and to rewind the motor, and a clutch between said escapement and movable contact, permitting of the quick return of the latter.

fl. The combination with the circuit-closing switch and the movable contact of a rheostat of a spring acting to open said switch and aetuate said movable contact to cut out resistance, an escapement governing the movement of said contact, andan actuating-aim adapted to close said switch and release saidvmovable contact when moved in one direction, and to return said contact and release said switch when moved in the opposite direction.

5. The combination with the circuit-opening switch and the movable contact of a rheostat, of a spring acting to open said switch and actuate said movable contact to cut out resistance, an escapement for governing the movement of said contact, an actuating-arm for closing said switch and releasing said m ovable contact when actuated in one direction and for returning said contact and releasing said switch when moved in the opposite direction7 a spring-latch on said switch with which said arm engages to close the switch, and an electricallyoperated latch for retaining said switch in its closed position.

G. The combination with the circuit-closing switch, the movable contact of the rheostat, and a motor for operating said movable contact to cut out resistance, upon the closing ot' said switch, of means forautomatically opening said switch upon the failure of cui-ren t1 and means for compelling the return of said movable contact before said switch can be again closed.

In testimony whereof I ailix my signature in presence of two witnesses.

GEORGE J. SCIINICIIN'LR.

I'Vitnesses:

M. B. ODoei-inirrv, Or'ro F. 1$Anfifitni,.

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